Heater having a helical fluid conveying coil



2 Sheets-Sheet 2.

H. M. PAULSEN HEATER HAVING A HELICAL FLUID CONVEYING COIL Sept. 4, 1951Filed June 2, 1945 H. M. PAUL-SEN HEATER HAVING A HELICAL FLUIDCONVEYING COIL Sept 4, 1951 2 Sheets-Sheet 2 Filed June 2, 1945 Z N V ENTOR.

ATTO/QNEYJ Patented Sept. 4, 1951 UNITED CONVEYING 'QQIL 7 Henry M.Paulsen, Long Beach, Calif.

Application June 2, 1945, Serial No. 597,312

' My'present invention has to do with heaters for raising thetemperature of fluids, such as petroleum oils, steam and gases, findingone of its chief uses and advantages as a heater for oils preliminary topassing them to a fractionator for separation of the components.

' In general, heaters for such purposesinvolve tubes through which thefluids are passed,- the tubes being securely mounted in a furnacestructure. In conventional heater construction of this type, paralleltubes are disposed one above the other across the furnace, projecting attheir ends through the furnace walls and being connected together on theoutside by U-connections. In cases wherein the straight tubes are not sosupported at their ends in the furnace walls, relatively expensivehangers are required. In either case provision is lacking for freemovement of the tube elements due to the considerable expansion andcontraction taking place in the tubes and there is no uniformity ofvelocity or any appreciable turbulence of the flow of the'fluids Whilepassing through the tubes. This shortcoming results in hot spotsrequiring relative- 1y expensive or high grades of tubing and alsoresults'in deposits on the tube walls which require frequent cleaning.Also, conventional heater construction of this sort is notconducivetomaximum thermal efiiciency and does not permit the use of sectionalfurnace construction which is so desirable sincethe refractorylining ofsuch furnaces must be repaired and renewed from time to time.

It is therefore among the objects of my invention to overcome thosedisadvantages as well as to provide additional advantages. Moreparticularly, it is an object to provide a fluid-passing coil helicallywound and disposed in a furnace in such manner that the heating flamemay be projected axially through the coil in a direction counter'to theflow of fluids through the coil and wherein heat reflected from therefractory walls may be utilized to the fullest advantage. 'Itis also anobject of my present invention to provide a device of this characterwherein .the fluid-passing tubes are so mounted in the furnace as toprovide for free expansive and contractive movement and as to require nohangers.

.It is a further object of the invention to provide fluid-heatingapparatus in which the fluids are passed through the tubes with uniformvelocity and turbulence and in which the tubes do not require frequentcleaning. When the tubes of my invention do have to be cleaned, whichisinot frequently, they may be readily, economically and efficientlycleaned.

It is another object of the invention to provide fluid-heating apparatuswherein. the explosion doors, are disposed in an area not covered byrefractory material, 4

3 Claims. (01. 122- 248) Another objeotis to provide fluid-heatingapparatus wherein there is minimum obstruction to the free flow of theproducts of combustion, thus improving the general eiiiciency of thedevice as well as enabling the use of a relatively short stack forwithdrawal of the products of combustion. v 1

Another objectof the invention i the provision of fluid-heatingapparatus wherein the heated fluid will leave the apparatus in mostefficient condition for subsequent fractionation.

It is a further object of the invention to provide fluid-heatingapparatus wherein it is possible to attain maximum tube surface with aminimum of refractory wall surface.

Theparticular spacing of the whorls of th tube from each other as wellas'from the refractory walls, which provide unexpectedly improvedresults, also constitutes one of the features of my invention.

While I have specifically mentioned some of its major objects andadvantages, my invention contemplates ad'ditional'object's and providesadditional advantages, all of'whichwill become apparent from thefollowing detailed explanation of one of the presently preferredadaptations embraced within the broader scope of my invention as definedby the appended claims.

For purposes of the following description I shall refer to theaccompanying drawings, in

Whichf Fig. l is a side elevation, some parts being shown "in section;

Fig. 2 is a section on line 2-2 of Fig. 1;

Fig. 3 is a section on line 3'-3 of Fig. 1;

Fig. 4 is an enlarge'd'section on'line 4-4 of Fi 1;

Fig. 5 is a cross-sectional vie-w showing a slightly modifiedstructure;'and

Fig. 6 is an enlarged perspective showing a fragment of the tube whorlspacer members.

Referring now to Fig.2 of the drawings I show generally at 5 a furnaceof circular cross section and comprised'of two semi-circular segments orsections 500,519. The lower section 5b has an arch of fire bricks 6 laidin a semi-circular metal shell i supportedupon legs 8, spacer bricks 9being embedded in the refractionarylining and spaced apartoircumferentially of the wall.

' The upper section 5a consists of aligned semicircular shell sectionsll having radial end flanges Ila secured together by bolts l'lb. Securedto the side edges of the respective sections I! are plates or flanges Itwhich are bolted to parallel flange members [9' carried by the lowershell 6 by'bolts 20. Fire brick lining I5 is carried by shell sectionsii, the side edges of the lining being supported'on the inwardlydisposed portions of plates l8.

In Figures 3 and 4 is shown a discharge stack 22 for the products ofcombustion disposed at right angles to the longitudinal axis of thefurnace, being in communication therewith through a flue 24. The stackhas the usual damper element 2,3, The flue' ha s openings 25 through itsside walls, which openings are normally closed by explosion doors 2'!hinged to the flue atZfi to swing relative thereto. The doorsareyieldably held closed by some suitable'means' 'sucht-as a spring notshown. The furnace has an end wall presenting an axial opening at withwhich the flue communicates, and has an opposite end wall 33 providedwith an axial opening 34 in which is disposed the fuel inletnozzle 35.

In Figuresl and 2 my improved fluid-passing coil, generally designated40, is comprised of a tube helicallyor spirally wound into a cylindricalshape, having a tangentially disposed inlet end 42 -au ,.ouletend 44, dends passing through openings in the side wallofthe furance.

' In Figs. 1, 2, and 5 the coil is'supported exclusively on the spacerbricks -9, the periphery of the coil being spaced. from the. refractoryWall preferably a distance equal to the outside diam eterof: the ,tubeof which the coil is formed. The Whorlsof the coil are also spaced aparta like distance-that is, a. distance equal to the outside diameter ofthe tube of which the coil is formed. For exampla for a coil formed of 3inch outside diameterflspirally wound tubin I find ,a furnace whose"refractory walls have an insideldiame'ter of the order of 6'? inches tobe particularly suitable, the spacing of the coil from the refractorywalls and the spacingrof the whorls from each other beingequal to theoutside diameter of the tubing of which the 'coilis formed, or ,3inchesl To maintain this spacing of the whorls of the tube from eachother and yet to allowifor free relative movement resulting fromfexpansjionf and contraction, I use U-shaped spacer .membiersiflsecured, as by. welding, to a met-als'trip 5|, a v

In a device such as described, constituted :in accordance with'inydnvention, it will be seen that the hot products ofcombustion passthrough the furnace in a directioncounter to the flow of the fluidsthrough the coil, '50 thatthe fluids leave the coil inethe mostefficient condition for subsequent} fractionation; This counter flowalso allow's the colder fluids'enteri'ng the coils to absorb heat fromthe colder gases or combustion thus taking advantage of heat usuallylost to atmosphere through .the stack. The stack. temperatures are alsokept at All tube surfaces are inside the furnace andin inti-. matecontact. with the'productsbf combustion, as well as in position touniformly take advantage of the heat reflection from 'ther'efractorywalls, thus insuring high thermal efficiency. The tur-' bulence and evenvelocity of flow through the coils eliminates all possibility of .localheating of the, tube, or "hot spotsjf and reduces to a minimumdeposition of residue on the tube walls. 'lfhis avoidance of hotspotsrenders it possible to use lower grades oftubing than wouldotherwise be the case.- The absence of bridge walls and other par-tsacting'as bafiles renders it possible to use a much shorter stack. Infact, in my device, a stack so short as not to require guy; wires orequivalent support may be used. Inasmuch the bottom portion of thelining, said members being disposed longitudinally of the furnace andspaced apart oircumferentially thereof, a cylindrical fluidepassing coilcomprised of helically 'woundtubing, said coil being disposed axially inas the coil merely :rests on thespaeer bricks, all a 7 tube hangers areeliminatedrand absolutely :free movement resulting fromexpansionandcontraction is possible.

the furnace and having its inlet end at one end of the furnaceand itsdischarge end at the other end of the furnace, said coil being supportedby the'spac'er' members in position coaxial with the furnace and withits periphery spaced from the lining a distance equal to the outsidediameter of the tubing, combustion means disposed to. pro- ;jectproducts of combustion axially of the'jcoil in a direction counter tothe direction of flow of fluid therethrough, and spacer meansiloose'lymounted on the coil to maintainits whorls spaced apart a distance equalto the outside diameter of the tubing, said spacer means each comprisingan elongated metal strip and U-shaped tube-fen- .gaging members securedto the strip at spaced points therealong.

- 2. .In a fluid heater, the combination of a horizontally disposedcylindrical furnace having a refractory lining, spacer members carriedby the bottom portion of the'lining, said members being disposedlongitudinally of .the furnace and spaced apart circumferentiallythereof, a cylindrical fluidepassingcoil comprised of helically woundtubing, saidcoil being disposed axially in the .furmice and having itsinlet end at one end of the furnace and its discharge end at the otherend ofthe furnace, said coil being supported bythe spacer membersimposition coaxial with the furnace, combustion means disposed toproject products of combustion-axially of the coil, and spacer stripsloosely mounted on the coil to maintain its whorls in predeterminedspaced relationship-to eachiother. 3.1m a flu-id; heater, thecombination of a horizontally disposed cylindrical furnace having arefractory lining, spacer members; carried :by the bottom portion of thelining,=.said members being disposed lon tud al y f the. furnace anspaced apart circumferentially.thereof, a cylinxdrical fluid-passingcoil comprised. of helically wound tubing,;said coil being disposedaxially in the furnace and havingitsinlet end at on 'end ofthe-furnaceand its d-ischargeend at the other end of thefurnace-combustion means disposed to project products of:combustionaxially of the coil, andrspacer means loosely mounted on thecoil to maintain its whorl spaced apart a distance equal o the outsidediameter of: the tubing; said spacer means each comprising an elongatedstrip-and Ll-shaped tube-engaging members secured to. the strip atspaced points therealong. V Y

' HENRY M. PAULSEN.

. REFERENCES CITED The following references are of record in the file ofthis patent:

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